Add pegmatite

[jeturcotte]

Like granites, pegmatite is made up of micas and feldspars and quartzes and the like, but with (sometimes MUCH) larger grain... in fact, pegmatites are commonly where pockets (vugs) large enough for intact crystals are located. Not sure if this should be a whole LAYER of stone, or a common vein in other igneous intrusive (not extrusive as it cools too fast) and metamorphic layers.

Once created, a LOT of gemstones will have to have it added to their locales... tourmalines, garnets, beryls, etc, are especially pristine when found in pegmatites.

[jeturcotte]

Due to larger quartz and feldspar crystals in the blend, pegmatite should probably be white, in game... but it might be worth considering a dark or medium grey background?